Van Helmont was one of the first scientists or alchemists to begin to understand and teach that the body is affected by chemicals and applied
chemical principles to physiological problems. One of the main things that
we may be grateful to van Helmont for is his development of the "scientific
method," in which experiments are carefully documented and observed.
Instead of using reason or thought to solve a chemical problem, one used
practical application and created an experiment which sometimes might yield
surprising results, results that were not available simply through the
thought process.
Van Helmont sought support for his theories in the Bible and teachings
of the ancient philosophers, but when he did practical experiments he found
that some results could not be accounted for by his theories. He did an
experiment to produce gas, which he believed was in everything and could be
released by heating. To prove this, he heated 62 pounds of charcoal and
found only 1 pound of ashes remained. The rest, 61 pounds, he concluded,
had changed into a spirit or...

His findings and theories on gases and the digestive process started
experimentation and thinking along those lines in the application of
medicine. He also introduced the concept of curing internal problems by
treating them with chemicals, tailored according to the specific complaints
which might arise in each individual. Van Helmont's theories put succeeding
scientists on the right track to discovering how chemicals and gases work.
Works Cited
Edwards, Quinn. "Photosynthesis and Optimizing Algae Growth in a
Bioreactor". Introduction to Biophotonics. Logan, Utah: Utah State
University. 28 Apr 2006.
.
NNDB. Jan Baptist van Helmont. Soylent Communications. 2006.
.